1. Field of the Invention
The present invention relates to an engine generator for driving a generator with an engine, a controller for the engine generator, an inverter-type engine generator arranged for converting the main output of a generator to an alternating current voltage by an inverter circuit, an engine starter apparatus arranged for protecting a starter motor from being excessively loaded at the start-up of an engine, and a remote-control system for the engine generator arranged for receiving and transmitting remote-control signals over an output line of the engine generator.
2. Description of the Related Art
(1) A modern engine generator is designed in which the on-timing for starting the supply of power from an igniter to the primary side of an ignition coil and the off-timing for canceling the supply of power from the igniter to generate a high voltage at the secondary side of the ignition coil are controlled by a microcomputer (a CPU).
More specifically, upon detecting the output signal of a pulser coil indicating that the engine rotating angle reaches a predetermined degree, the microcomputer calculates the on-timing and the off-timing on the basis of the engine speed and actuates the igniter from the on-timing to the off-timing to energize the primary side of the ignition coil.
In an engine generator having the engine started by a starter motor, the starter motor when energized for starting the engine draws a rush current and sharply increases the consumption of power instantly thus declining the battery voltage temporarily. When the microcomputer in the generating system is energized by a battery, its action may be unstable at the start-up of the engine or it may be reset.
For eliminating the above drawback, the conventional engine generator has an exciter winding provided on the generator in addition to the main windings for energizing the microcomputer.
The driving duration of the igniter depends on the source voltage. If the source voltage is low, the driving duration of the igniter or an interval between the on-timing and the off-timing is increased thus decreasing the operable period of the CPU. As a result, the CPU may fail to calculate the timing and the power generation will hardly be improved in the efficiency.
When the microcomputer is energized directly from the exciter winding, its source voltage will not be declined at the start-up of the engine. It is however necessary for feeding the microcomputer with an operable level of voltage at a minimum or cranking speed of the engine at the start-up to increase the size of the exciter winding. This may develop an excessively large level of voltage when the engine runs at a high speed.
(2) FIG. 22 is a block diagram showing a primary part of a conventional inverter type engine generator. A three-phase alternating current generator G is driven by an engine E. An AC output of the generator G is smoothed and converted to a DC form by a rectifying-smoothing circuit 61. A DC output of the rectifying-smoothing circuit 61 is then converted by an inverter circuit 62 to an AC output at a specific frequency.
The generator G has three-phase main windings C wound on a number (e.g. twenty one poles) of magnetic poles as some of full (e.g. twenty four) magnetic poles for generating a main output. Wound on the remaining (or three) of the magnetic poles are an inverter source coil 82, a battery charging coil 83, and an external DC source coil 84.
In the prior art shown in FIG. 22, each of the inverter source oil 82, the battery charging coil 83, and the other sub coil 84 holds one magnetic pole. Accordingly, when the total number of magnetic poles is 24 in the generator, only twenty one poles are assigned to the main output. Assuming that the main output is 4200 W, each of 21 magnetic poles undertakes 200 W. Consequently, each of the sub coils 82, 83, and 84 shares 200 W.
As the output of each of the sub coils 82, 83, and 84 is drawn only 10 to 15 W, 200 W is too large. On the other hand, the output of the main windings C may be too small for the size of the generator G.
(3) A conventional engine starter apparatus using a starter motor is provided for switching its ignition switch on to start an engine igniter. Then, when a starter switch is switched on, the start motor starts rotating. When the starter switch is turned off, the starter motor stops its action. More specifically, a driver presses the starter switch to actuate the starter motor and when the engine is started, releases the starter switch to stop the starter motor.
The starter motor consists mainly of a drive motor and a starter pinion gear. As the drive motor is rotated, the pinion gear is driven by its inertia to move into and engage with a ring gear mounted on the outer rim of a flywheel and the engine is cranked.
FIGS. 23 and 24 are timing charts showing the actions of relevant components at the start and stop of the engine in the prior art.
While the engine is being driven, the ignition switch is shifted at t1 from the on state to the off state. This cancels the action of the engine igniter thus gradually decreasing the engine speed. When the ignition switch is turned on just before the engine stops at t2, the action of the engine igniter is returned. If the engine is ignited again before the piston reaches the upper dead point for a compression process, it may rotate in a reverse direction thus exerting an excessive load to the starter motor. This phenomenon is known as xe2x80x9cback kickingxe2x80x9d.
When the piston fails to complete the compression process before the engine stops and the engine rotates in a reverse direction, the switching on of the starter switch at t3 starts the starter motor and throws its pinion gear into the ring gear which rotates in the reverse direction. This is also known as xe2x80x9creverse re-throwingxe2x80x9d and may exert an excessive load on the starter motor.
Also, once the starter motor is started, it continues to rotate even if the engine speed exceeds its complete combustion speed until it is switched off.
As shown in FIG. 24, when the engine fails to be started, the ignition switch remains turned on. Accordingly, when the piston fails to complete the compression process, the engine is ignited prior to the upper dead point thus developing an event of back kicking.
The prior art is only implemented by a rigid structure capable of bearing the excessive load generated in the back kicking or reverse re-throwing of the starter motor which is thus increased in the overall dimensions.
(4) The conventional engine generator having a power generator driven by an engine is connected from its body to a remote controller box by a remote control cable of substantially 10 meters. The remote controller box includes an engine switch for connecting the engine with a main source, a start switch for driving a starter motor to crank the engine, a pilot lamp for indicating that the engine generator is in action, and soon. The engine generator can thus be controlled from a remote location with the remote controller box.
The engine generator may of ten be sited close to an electric apparatuses to be energized. As the remote control cable connects between the engine generator and the remote controller box, it will interrupt the engine generator from being moved to a desired location.
Also, the engine generator has a receptacle provided on the main body thereof for directly accepting a plug from the electric apparatus to be energized and may allow its receptacle to be joined with the plug of an extension cable from the electric apparatus. As the electric apparatus is energized via the extension cable from the engine generator which is spaced significantly from the electric apparatus, the remote controller cable has to be extended for remote controlling the electric apparatus.
In the prior art, any error developed on the engine generator can hardly be notified by the remote controller box. In case that the operator of the remote controller box works out of sight of the engine generator, it may fail to recognize the error of the engine generator within a short time.
A first object of the present invention is provide an engine generator which is small in the size but high in the efficiency of power generation and a controller for the engine generator. A second object of the present invention is to provide an engine generator which is high in the efficiency of power generation. A third object of the present invention is to provide an engine starter apparatus which can start an engine with generating no event of back kicking or reverse re-throwing. A fourth object of the present invention is to provide a remote control system for an engine generator which is improved in the maneuverability and the mobility.
The first object of the present invention is implemented by the following features (1), (2).
(1) An engine generator of the present invention comprising a power generator driven by an engine, a starter motor for cranking the engine, and a controller for controlling various electric loads including the start motor with a driving voltage which depends on the power supplied from the generator and a battery. The controller including a voltage drop limiting means for minimizing a decrease in the driving voltage in the action of the starter motor.
(2) A controller for an engine generator of the present invention supplies various electric loads including a starter motor with a driving voltage which depends on the power received from a generator and a battery. The controller comprising a voltage drop limiting means for minimizing a decrease in the driving voltage in the action of the starter motor.
According to the feature (1), (2), the driving voltage supplied from the igniter of the controller to the primary side of the ignition coil is not declined when the power consumption of the battery increases at the startup of the starter motor. This allows the on period of the igniter to be shortened during the cranking action of the starter motor, hence ensuring the duration for the CPU calculating the timing of ignition. Accordingly, as the timing of ignition is calculated at higher accuracy, the engine generator can be improved in the efficiency of power generation and its controller can be implemented.
The second object of the present invention is implemented by the following features (3), (4).
(3) An engine generator of the present invention having an alternating current generator driven by an engine, a rectifier circuit for rectifying a main output released from the output terminal of the alternating current generator, an inverter circuit for converting an output of the rectifier circuit into an alternating voltage, and a transformer connected at its primary side to the output terminal of the alternating current generator. A part of the main output of the alternating current generator can be drawn out from the secondary side of the transformer and used as an internal power supply.
(4) An engine generator of the present invention is constituted that the secondary side of the transformer incorporates two or more sub-coils. Each sub-coil arranged for energizing a corresponding electric load.
According to the feature (3), as the ratio between the primary coil and the secondary coil of the transformer is determined to meet the requirement of power as the internal power supply, the output of the AC generator can be used at higher efficiency and released at higher effectiveness.
According to the feature (4), the windings of each sub-coil can be determined to meet the power consumption of its corresponding electric load which is energized by an internal power supply. This allows a desired power of the internal power supply to be accurately drawn out from the main output of the alternating current generator, thus improving the efficiency of power generation.
The third object of the present invention is implemented by the following features (5), (6).
(5) An engine starter apparatus of the present invention comprising a starter motor to crank an engine, a start switch for starting the engine, an igniting means for combusting the engine at specific timing, and a controller for controlling the action of the starter motor and the igniting means on the basis of the engine speed. The controller arranged for canceling the action of the starter motor when the engine speed in the cranking action exceeds a first reference and then inhibiting the action of the igniting means when the engine speed becomes lower than a second reference speed.
(6) An engine starter apparatus of the present invention comprising a starter motor to crank an engine, a start switch for starting the engine, an igniting means for combusting the engine at specific timing, and a controller for controlling the action of the starter motor and the igniting means on the basis of the engine speed. The controller including an engine stop examining means for examining from the engine speed whether the engine is in action or not, wherein the starter motor and the igniting means are switched on when the start switch is turned on and the engine stop examining means judges that the engine is not in action.
According to the feature (5), the action of the starter motor is automatically canceled when the engine speed exceeds the first engine speed. As the first engine speed is set equal to the complete combustion speed, the action of the starter motor will never continue once the engine is in action. The action of the igniting means is inhibited when the engine speed drops down to below the second engine speed, hence inhibiting any back kicking just before the action of the engine stops.
According to the feature (6), the action of the starter motor and the igniting means is inhibited when the engine is in action, regardless of the on state of the start switch. This can allow no reverse re-throwing of the starter pinion gear when the starter motor is driven with the engine running in a reverse direction or producing a back kicking just before its action stops.
The fourth object of the present invention is implemented by the following feature (7).
(7) A remote control system of the present invention comprising an engine generator, a transponder connected to a power line of the engine generator, and a remote controller for communication with the transponder over a radio link. A remote control signal is exchanged in two ways across the transponder between the engine generator and the remote controller and the remote control signal is transferred between the engine generator and the transponder over the power line of the engine generator.
According to the feature (7), the remote controller and the transponder are communicated over a radio link, thus eliminating the use of cables. Also, the exchange of the remote control signal between the engine generator and the transponder is made over the output line of the engine generator, hence eliminating the use of a dedicated cord for transmitting and receiving the remote control signal between the engine generator and the transponder. Moreover, as the radio communication is carried out over a small distance between the remote controller and the transponder, its hardware arrangement can be simple and less expensive.